It’s a quirk of human nature that many of us enjoy sad music. Research last year uncovered some reasons why, including feeling a sense of connection, and the aesthetic appeal. For a new study, Kazuma Mori and Makoto Iwanaga drilled down into the specific situation where sad lyrics are combined with happy music, as in the Beatles’ Hello, Goodbye. They wanted to see how people would respond to the music or lyrics in isolation, and how this differed from their response to the two together.

Fifty-three Japanese students listened to two happy-sounding songs that have sad lyrics: Och Jag Grät Mig Till Sömns Efter Alla Dar, and Regresa a Mi (Unchain My Heart in English). The first, a Swedish song, is fast tempo and in a major key, but the lyrics are about adolescent angst. The second, in Spanish, also has a fast tempo and is in a major key, but the lyrics are about broken hearts and regret.

The students first listened to the music alone, then they read the lyrics (translated into Japanese) without any music, and finally, they listened to the music while also seeing the translated lyrics. Results were combined for the two songs. As you’d expect, the students said they perceived the happy music alone to be happier than the sad lyrics alone, or the music plus lyrics. Also, they perceived the lyrics alone as sadder than the music plus the lyrics.

What about the students’ feelings? Here’s where things get more intriguing. The students reported feeling just as happy after hearing the music plus the sad lyrics, as they did when they heard the music alone. In contrast, they felt sad when exposed to the lyrics in isolation. In other words, when combined with a happy melody, the effect of the sad lyrics was transformed.

The researchers also compared associations between the students’ perceptions of the music and/or lyrics, and their subsequent feelings. The perceived happiness of the music or lyrics alone was related to how much happiness the students reported feeling. That makes sense. More curiously, when it came to music plus lyrics, it was the students’ perception of the sadness of this combination that went hand in hand with their experiencing more happiness. It’s as if the students recognised that the songs’ message was sad, but in combination with an upbeat melody, this sad message provoked positive emotion.

What happens in the mind of a listener when sad lyrics are blended with happy tunes? Mori and Iwanaga believe a sad/happy combination “captures something about the complexity of emotion” that we find aesthetically pleasing, triggering what they call “polyvalent pleasant feelings.” At a physical level, they think an upbeat melody triggers the release of the hormone prolactin, which is associated with calmness. With this relaxing chemical accompaniment, they say, sad feelings can be experienced “without … real psychic pain.”